Standards used in Delta Chat

Some of the standards Delta Chat is based on:

Tasks	Standards
Transport	IMAP v4 (RFC 3501), SMTP (RFC 5321) and Internet Message Format (IMF, RFC 5322)
Embedded media	MIME Document Series (RFC 2045, RFC 2046), Content-Disposition Header (RFC 2183), Multipart/Related (RFC 2387)
Identify server folders	IMAP LIST Extension (RFC 6154)
Push	IMAP IDLE (RFC 2177)
Authorization	OAuth2 (RFC 6749)
End-to-end encryption	Autocrypt Level 1, OpenPGP (RFC 4880) and Security Multiparts for MIME (RFC 1847)
Configuration assistance	Autoconfigure and Autodiscover
Messenger functions	Email-chat
Detect mailing list	List-Id (RFC 2919) and Precedence (RFC 3834)
Send and receive system messages	Multipart/Report Media Type (RFC 6522)
Return receipts	Message Disposition Notification (MDN, RFC 8098, RFC 3503) using the Chat-Disposition-Notification-To header